The primary goal of this study is to examine the neuropsychological functioning of emphysema patients undergoing lung volume reduction surgery (MT+LVRS) compared to medical therapy alone (MT). The study will include patients at two clinical sites for the National Emphysema Treatment Trial (NETT). Enhancements of ventilation and functional capacity are expected to contribute to greater long-term improvements in utilization of oxygen in the brain, thereby leading to improvements in cognitive performance greater than those observed among patients who exercise but do not receive LVRS (Specific Aim 1). A health control group will be retested on similar neuropsychological tests in order to control for practice effects (Specific Aim 2). Although we do not expect significant differences in emotional (depression and anxiety) functioning across groups, this study will enable us to evaluate the relationship between emotional status and neuropsychological scores in the MT+ LVRS and MT groups following randomization. In addition, since major neurological events are more likely following surgery, and major neurological events affect cognitive function, we will evaluate the incidence of neurological events in our sample and will determine the degree to which neurological events are associated with cognitive function (Specific Aim 3). No studies have examined the relationship between change in cognition and improve quality of life in COPD patients following LVRS surgery, therefore, we aim to explore these associations in Specific Aim 4. We propose to compare changes following LVRS and MT by examining 84 NETT patients (42 in MT, 42 in LVRS) at three times points (baseline, post 6-10 week medical treatment MT, and 6 months post MT or LVRS randomization) using select neuropsychological, psychological, neurological and QoL tests. Forty normal controls will be tested at baseline and 6-10 weeks follow- up.